Traditional Agrosystems Research Articles

Evolution of the rice blast pathogen on spatially structured rice landraces maintains multiple generalist fungal lineages.

Traditional agrosystems, where humans, crops and microbes have coevolved over long periods, can serve as models to understand the ecoevolutionary determinants of disease dynamics and help the engineering of durably resistant agrosystems. Here, we investigated the genetic and phenotypic relationship between rice (Oryza sativa) landraces and their rice blast pathogen (Pyricularia oryzae) in the traditional Yuanyang terraces of flooded rice paddies in China, where rice landraces have been grown and bred over centuries without significant disease outbreaks. Analyses of genetic subdivision revealed that indica rice plants clustered according to landrace names. Three new diverse lineages of rice blast specific to the Yuanyang terraces coexisted with lineages previously detected at the worldwide scale. Population subdivision in the pathogen population did not mirror pattern of population subdivision in the host. Measuring the pathogenicity of rice blast isolates on landraces revealed generalist life history traits. Our results suggest that the implementation of disease control strategies based on the emergence or maintenance of a generalist lifestyle in pathogens may sustainably reduce the burden of disease in crops.

Small-scale farming in drylands: New models for resilient practices of millet and sorghum cultivation.

Finger millet, pearl millet and sorghum are amongst the most important drought-tolerant crops worldwide. They constitute primary staple crops in drylands, where their production is known to date back over 5000 years ago. Compared to other crops, millets and sorghum have received less attention until very recently, and their production has been progressively reduced in the last 50 years. Here, we present new models that focus on the ecological factors driving finger millet, pearl millet and sorghum traditional cultivation, with a global perspective. The interaction between environment and traditional agrosystems was investigated by Redundancy Analysis of published literature and tested against novel ethnographic data. Contrary to earlier beliefs, our models show that the total annual precipitation is not the most determinant factor in shaping millet and sorghum agriculture. Instead, our results point to the importance of other variables such as the duration of the plant growing cycle, soil water-holding capacity or soil nutrient availability. This highlights the potential of finger millet, pearl millet and sorghum traditional cultivation practices as a response to recent increase of aridity levels worldwide. Ultimately, these practices can play a pivotal role for resilience and sustainability of dryland agriculture.

Diversity and ecological importance of plants in traditional agroforestry of Sudano-sahelian domain of Cameroon: case of Meri in the Mandara Mountains

Sudano-Sahelian domain is the poorest in biodiversity because of the climate which is unfavourable compared to the equatorial climate. The unsustainable agricultural practices associated with this climatic roughness are among the main factors of habitat destruction, hence the destruction of biodiversity in this phytogeographic environment. In order to valorize and conserve sudano-sahelian plant resources, a study was carried out in seasonal agrosystems in the Mandara Mountains. The Diversity and the floristic diversity were assessed. Inventories of woody plants were done in 16 plots (100 m x 100 m) grouped in 4 localities/villages. The circumference of the trunk of all the inventoried plants (circonference ≥ 10 cm) was measured. In total, 64 species grouped 45 genera and 27 families were inventoried. The highest FIV was obtained for Mimosaceae (FIV = 104.51) and Combretaceae (FIV = 51.22), the other families had FIV < 30. Diversities in the localities (Shannon index ranging from 2.82 to 2.86 bits) were lower than diversity in whole stand (Shannon index = 3.09 bits). Acacia albida (IVI = 53.52, RI = 6.25), Acacia nilotica (IVI = 9.18, RI = 18.75), Acacia seyal (IVI = 5.19, RI = 43.75), Anogeissus leiocarpus (IVI) = 41.82, RI = 0), Balanites aegyptiaca (IVI = 14.23, RI = 12.50), Diospyros mespiliformis (IVI = 9.91, RI = 37.50), Tamarindus indica (IVI = 16.35, RI = 12.5), and Ziziphus mauritiana (IVI = 9.52, RI = 31.25) were observed in all localities. There were considered as characteristics and represent the floristic background of the stand. Traditional agrosystems can be considered as tools for the conservation of wild species useful to local populations. It would be imperative to conserve in situ wild species, source of genetic diversity for their sustainable use.

Sesame response to nitrogen management under contrasting water availabilities

Sesame is mainly cultivated under traditional, low-input agro-systems. Recent breeding developments promoted the modernization and mechanization of sesame cultivation. However, only a few articles have been published concerning fertilization requirements for both modern and traditional agro-systems. In field trials at two locations, we determined the response of irrigated sesame to nitrogen (N). Three promising sesame lines were tested combining two irrigation levels with four N levels. At a high irrigation level, N had a significant effect on growth, branching, and consequently, seed yield exceeding two-ton ha−1. A high N doze was accompanied by a decrease in the photosynthetic rate and leaf water potential. The δ13C confirmed lower stomatal conductance under high N treatments. Under deficit irrigation, the N level had a minor effect on the monitored parameters, indicating N fertilization was not efficient. Seed oil content was negatively correlated with seed N concentration. Our results question the necessity of N application when water is limited, as N fertilization promotes vigorous development that rapidly depletes soil water. Thus, water availability should be considered when developing an N management strategy. For high-yielding agro-systems, roughly 80–120 ​kg ​ha−1 N is required for optimal yield, bearing in mind the negative association between seed-N and oil content.

Sustainable Transfer of Tomato Landraces to Modern Cropping Systems: The Effects of Environmental Conditions and Management Practices on Long-Shelf-Life Tomatoes

The individual effects of biotic and abiotic factors on tomatoes have been widely reported. However, under commercial conditions, multiple interactions between factors occur, masking or even changing the direction of their effects in some cases. Here we report a comprehensive analysis of preharvest factors affecting yield, quality (soluble solids content, fruit color, and firmness), and shelf-life of long-shelf-life Mediterranean varieties of tomatoes. We studied five long-shelf-life genotypes under 16 growing environments, including tunnel and open-air systems and suboptimal to excessive fertigation (22–142% crop evapotranspiration). The results enabled us to classify traits into three groups according to the importance of the contributions of different types of factors: mainly genotype (ripening earliness and firmness), genotype plus environment (yield, fruit weight, water-use efficiency (WUE)), or genotype plus environment plus the interaction between genotype and environment (cracking, soluble solids content, and shelf-life). Under similar management practices, open-air conditions optimized yields, and high fertigation doses improved yield and marketability (firmness), but reduced quality (redness and soluble solids content). WUE was maximized under low-input cropping systems (comparable to traditional agrosystems), and the balance between WUE and yield was optimized when fertigation was adjusted to the requirements of the crop. Shelf-life was negatively correlated with high-yielding environments, and day–night amplitude in relative humidity was strongly correlated with the incidence of fruit cracking. The present study sheds light on the contributions of environment and management practices on tomato yield and quality, and provides a basis on which to select better management practices for the novel commercial group of European long-shelf-life tomato landraces.

Is GIAHS an Effective Instrument to Promote Agrosystem Conservation? A Rural Community's Perceptions

The Globally Important Agricultural Heritage System (GIAHS) has been established by FAO to protect valuable agricultural systems that are rich in biodiversity and home to indigenous knowledge, technology and cultural values. GIAHS has been accepted by many countries as a tool to maintain traditional agrosystems as “living heritage”. This paper examined the Xinghua Duotian agrosystem in eastern China to explore whether the GIAHS programme is an effective instrument for top-down implementation of conservation policies initiated by the government. An intensive social survey using a questionnaire was conducted in the core conservation area to examine farmers' understanding of the agrosystem and their willingness to conserve it. Statistical analyses including factor analysis, a linear model, a logit model and an optimal scale model were used to reveal farmers' perception of GIAHS and the factors that impact their willingness to conserve. Results show that the agrosystem faces challenges of aging and population loss. Farmers were not very familiar with GIAHS. They did not link GIAHS to the agrosystem because they generally understood GIAHS as a title meant to bring economic benefits, although they also thought the agrosystem had non-economic values worth conserving. Because farmers were not sure about the economic outcomes of the GIAHS programme, they thought the government, not them, should take the main role in conservation. Therefore, GIAHS as a tool to encourage farmers to become active in conservation does not seem very effective. It will not become so until it truly facilitates the transformation of non-economic values to economic values in the agrosystem. We suggested that the concepts of GIAHS should be matched to farmers' perceptions to provide farmers with conservation incentives.

On the origins and domestication of the olive: a review and perspectives.

Background Unravelling domestication processes is crucial for understanding how species respond to anthropogenic pressures, forecasting crop responses to future global changes and improving breeding programmes. Domestication processes for clonally propagated perennials differ markedly from those for seed-propagated annual crops, mostly due to long generation times, clonal propagation and recurrent admixture with local forms, leading to a limited number of generations of selection from wild ancestors. However, additional case studies are required to document this process more fully. Scope The olive is an iconic species in Mediterranean cultural history. Its multiple uses and omnipresence in traditional agrosystems have made this species an economic pillar and cornerstone of Mediterranean agriculture. However, major questions about the domestication history of the olive remain unanswered. New paleobotanical, archeological, historical and molecular data have recently accumulated for olive, making it timely to carry out a critical re-evaluation of the biogeography of wild olives and the history of their cultivation. We review here the chronological history of wild olives and discuss the questions that remain unanswered, or even unasked, about their domestication history in the Mediterranean Basin. We argue that more detailed ecological genomics studies of wild and cultivated olives are crucial to improve our understanding of olive domestication. Multidisciplinary research integrating genomics, metagenomics and community ecology will make it possible to decipher the evolutionary ecology of one of the most iconic domesticated fruit trees worldwide. Conclusion The olive is a relevant model for improving our knowledge of domestication processes in clonally propagated perennial crops, particularly those of the Mediterranean Basin. Future studies on the ecological and genomic shifts linked to domestication in olive and its associated community will provide insight into the phenotypic and molecular bases of crop adaptation to human uses.

On the origins and domestication of the olive: a review and perspectives.

Unravelling domestication processes is crucial for understanding how species respond to anthropogenic pressures, forecasting crop responses to future global changes and improving breeding programmes. Domestication processes for clonally propagated perennials differ markedly from those for seed-propagated annual crops, mostly due to long generation times, clonal propagation and recurrent admixture with local forms, leading to a limited number of generations of selection from wild ancestors. However, additional case studies are required to document this process more fully. The olive is an iconic species in Mediterranean cultural history. Its multiple uses and omnipresence in traditional agrosystems have made this species an economic pillar and cornerstone of Mediterranean agriculture. However, major questions about the domestication history of the olive remain unanswered. New paleobotanical, archeological, historical and molecular data have recently accumulated for olive, making it timely to carry out a critical re-evaluation of the biogeography of wild olives and the history of their cultivation. We review here the chronological history of wild olives and discuss the questions that remain unanswered, or even unasked, about their domestication history in the Mediterranean Basin. We argue that more detailed ecological genomics studies of wild and cultivated olives are crucial to improve our understanding of olive domestication. Multidisciplinary research integrating genomics, metagenomics and community ecology will make it possible to decipher the evolutionary ecology of one of the most iconic domesticated fruit trees worldwide. The olive is a relevant model for improving our knowledge of domestication processes in clonally propagated perennial crops, particularly those of the Mediterranean Basin. Future studies on the ecological and genomic shifts linked to domestication in olive and its associated community will provide insight into the phenotypic and molecular bases of crop adaptation to human uses.

Disentangling the effect of farming practice from aridity on crop stable isotope values: A present-day model from Morocco and its application to early farming sites in the eastern Mediterranean

Agriculture has played a pivotal role in shaping landscapes, soils and vegetation. Developing a better understanding of early farming practices can contribute to wider questions regarding the long-term impact of farming and its nature in comparison with present-day traditional agrosystems. In this study we determine stable carbon and nitrogen isotope values of barley grains from a series of present-day traditionally managed farming plots in Morocco, capturing a range of annual rainfall and farming practices. This allows a framework to be developed to refine current isotopic approaches used to infer manuring intensity and crop water status in (semi-)arid regions. This method has been applied to charred crop remains from two early farming sites in the eastern Mediterranean: Abu Hureyra and ‘Ain Ghazal. In this way, our study enhances knowledge of agricultural practice in the past, adding to understanding of how people have shaped and adapted to their environment over thousands of years.

Root crops diversity and agricultural resilience: a case study of traditional agrosystems in Vanuatu (Oceania)

In Vanuatu (Oceania), small-scale farmers’ subsistence still largely relies on the sustainable use and maintenance of a wide-ranging biodiversity out of which root and tuber crops provide the bulk of daily subsistence. In neighboring countries, foreign influence since the first European contacts, further associated changes and the introduction of new crop species have induced a loss of cultivated diversity. This paper presents a baseline study of the diversity of root and tuber crops in ten communities throughout Vanuatu. In a context where the smallholders’ agrosystems are increasingly considered as key components for the global conservation of crop genetic resources, this study provides clues to better understand the effective roles of biodiversity in traditional agrosystems. It also provides insights on the rationale behind the constitution of agricultural portfolios and discusses how the cultivated diversity allows communities to cope with changes and pressures. The paper also shows that recently introduced crops neither seem to have compromised agricultural diversity nor drastically changed the agrosystems in Vanuatu. On the contrary, such crops are used by farmers to strengthen the resilience of their agrosystems. A discussion then presents the idea of continuity through change and novelty as a critical factor for resilience. The paper concludes by discussing the role of indigenous agriculture and culture in ensuring food security and in development strategies in a larger context.

Towards a comprehensive characterization of durum wheat landraces in Moroccan traditional agrosystems: analysing genetic diversity in the light of geography, farmers' taxonomy and tetraploid wheat domestication history.

BackgroundCrop diversity managed by smallholder farmers in traditional agrosystems is the outcome of historical and current processes interacting at various spatial scales, and influenced by factors such as farming practices and environmental pressures. Only recently have studies started to consider the complexity of these processes instead of simply describing diversity for breeding purposes. A first step in that aim is to add multiple references to the collection of genetic data, including the farmers’ varietal taxonomy and practices and the historical background of the crop.ResultsOn the basis of interview data collected in a previous study, we sampled 166 populations of durum wheat varieties in two traditional Moroccan agrosystems, in the Pre-Rif and Atlas Mountains regions. Using a common garden experiment, we detected a high phenotypic variability on traits indicative of taxonomical position and breeding status, namely spike shape and plant height. Populations often combined modern (short) with traditional-like (tall) statures, and classical durum squared spike shape (5 flowers/spikelet) with flat spike shape (3 flowers/ spikelet) representative of primitive domesticated tetraploid wheat (ssp. dicoccum). By contrast, the genetic diversity assessed using 14 microsatellite markers was relatively limited. When compared to the genetic diversity found in a large collection of tetraploid wheat, it corresponded to free-threshing tetraploid wheat. Within Morocco, the two studied regions differed for both genetic diversity and variety names. Within regions, neither geography nor variety names nor even breeding status constituted strong barriers to gene exchange despite a few significant patterns.ConclusionsThis first assessment of morphological and genetic diversity allowed pointing out some important factors that may have influenced the structure and evolutionary dynamics of durum wheat in Morocco: the significance of variety names, the occurrence of mixtures within populations, the relative strength of seed exchange between farmers and local adaptation, as well as the fate of modern varieties once they have been introduced. Further, multidisciplinary studies at different spatial scales are needed to better understand these complex agrosystems of invaluable importance for food security.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-014-0264-2) contains supplementary material, which is available to authorized users.

Dynamic integration of sustainability indicators in insular socio-ecological systems

The sustainability assessment on socio-ecological systems requires a systemic perspective in order to address the close relationships between the environmental and socio-economic processes. This need is especially urgent in the case of arid insular systems where limiting factors, as land and water resources, are more evident. The hyperarid island of Fuerteventura (The Canary Islands, Spain) represents a challenging case due to the need for compatibilizing the rising tourist development with the sustainable management of its natural resources, highly vulnerable due to processes such as the degradation of natural habitats – which hosts endemic and endangered species – or the high dependence of allocthonous energy sources for basic processes, including water supply.In this work we present an integral dynamic model, the Fuerteventura sustainability model (FSM), tested and calibrated for 1996–2011 period. The FSM allows to understand the main components of this socio-ecological system and their changes along time, as well as the interaction between the included sustainability indicators and other factors within the system. Results have shown the existence of potential trade-offs not only between socioeconomic development and conservation options, but also between sustainability goals under different management options. The conservation of the Houbara habitat might require the elimination of traditional agro-systems restoration plans, although these agro-systems offer important environmental functions. Besides, a reduction of cattle herd in order to control the degradation of high quality vegetation might negatively affect the endangered population of scavengers on the island. The water–energy binomial offers another trade-off regarding sustainable development, due to the strong dependency of the water availability on energy consumption. In this sense, the FSM has shown to be a useful tool to improve the comprehensive diagnosis of the system and to identify trade-offs between sustainability indicators to orientate management policies for this insular socio-ecological system.

Anchoring durum wheat diversity in the reality of traditional agricultural systems: varieties, seed management, and farmers' perception in two Moroccan regions.

BackgroundTraditional agrosystems are the places were crop species have evolved and continue to evolve under a combination of human and environmental pressures. A better knowledge of the mechanisms underlying the dynamics of crop diversity in these agrosystems is crucial to sustain food security and farmers’ self-reliance. It requires as a first step, anchoring a description of the available diversity in its geographical, environmental, cultural and socio-economic context.MethodsWe conducted interviews with farmers cultivating durum wheat in two contrasted traditional agrosystems of Morocco in the Pre-Rif (163 farmers) and in the oases of the Atlas Mountains (110 farmers). We documented the varietal diversity of durum wheat, the main characteristics of the farms, the farming and seed management practices applied to durum wheat, and the farmers’ perception of their varieties.ResultsAs expected in traditional agrosystems, farmers largely practiced diversified subsistence agriculture on small plots and relied on on-farm seed production or informal seed exchange networks. Heterogeneity nevertheless prevailed on many variables, especially on the modernization of practices in the Pre-Rif region. Fourteen (resp. 11) traditional and 5 (resp. 3) modern varieties were identified in the Pre-Rif region (resp. in the Atlas Mountains). The majority of farmers grew a single variety, and most traditional varieties were distributed in restricted geographical areas. At the farm level, more than half of the varieties were renewed in the last decade in the Pre-Rif, a more rapid renewal than in the Atlas Mountain. Modern varieties were more prevalent in the Pre-Rif region and were integrated in the traditional practices of seed production, selection and exchange. They were clearly distinguished by the farmers from the landraces, the last ones being appreciated for their quality traits.ConclusionsThe surveyed traditional agrosystems constitute open, dynamic and heterogeneous entities. We suggest that competing factors could favour or limit the cultivation of improved varieties and the erosion of original durum wheat diversity. This first description opens the way to focused further investigations, including complementing variety names with cultural, genetic and phenotypic information and unravelling the multidimensional factors and consequences of modern variety adoption.

Life cycle assessment of coupling household biogas production to agricultural industry: A case study of biogas-linked persimmon cultivation and processing system

Biogas plant construction has been boosted in rural China not only due to the immediate merit from biogas production but also the succeeding benefit from by-product utilization in agro-industry, both of which are significant strategies to address energy shortage and global warming issues. However, little work has been done to evaluate the coupling of biogas projects to traditional agrosystems from a life-cycle perspective, which is most important in process and system optimization in different senses. By taking persimmon cultivation and processing with supports from a household biogas plant as a case study, this study conducts a life cycle assessment of coupling biogas production to agro-industry in terms of energy, environmental and economic performance. The results suggest that each production stage following the biogas/digestate utilization chain (biogas operation-persimmon cultivation-product processing) is beneficial across all three aspects. However, a tradeoff only exists in utilizing digestate as top-dressing and employing biogas utilization as engine fuel, while biogas application in fresh-keeping and digestate reuse as base fertilizer fails to increase either energy production or greenhouse gas mitigation. The coupled system can be hopefully optimized through increasing fermentation efficiency and joint operation of biogas digesters.

Agro-morphological variability of rice species collected from Niger

Niger harbours a wealth of diversity of Africa's rice (Oryza glaberrima) and its related wild species. We therefore engaged in a collecting mission of rice species across growing regions and agrosystems in Niger. A total of 270 rice accessions were assembled, including 177 Asian rice (O. sativa) cultivars, 67 African rice landraces (O.glaberrima), 25 O. barthii and one O.longistaminata. We found most accessions (80.7%) along the Niger River and its tributary the Dallol Maouri. Many of the accessions, except those belonging to the wild O. barthii initially found around the Lake Chad region, were also collected along the Niger River. Drought, insects, birds, rice yellow mottle virus and bacterial blight were noted as major constraints on rice production. Accession naming by farmers was consistent within regions but seldom across regions. Based on the recorded agro-morphological traits, the germplasm was classified into three clusters: (1) O. longistaminata with floating African landraces and late-maturing floating Asian rice; (2) lowland O.barthii and African landraces; (3) a mixture of irrigated Asian rice with lowland accessions of both cultivated species. The phenotypic variability of the germplasm collection, as measured by the Shannon–Weaver diversity index, was relatively high (H′ = 0.69), with accessions in the irrigated agrosystem being less diverse than those in the traditional agrosystems. There was no significant difference in the magnitude of diversity between the main eco-geographical zones and between the clusters. However, some traits contributing the most to this diversity were different. This study suggested a substantial germplasm exchange between regions in Niger.

AN ECOLOGICALLY INTENSIVE APPROACH FOR THE DESIGN OF SUSTAINABLE HORTICULTURAL SYSTEMS IN THE TROPICS

Fruit and vegetable growers in the tropics are faced with crop protection issues resulting in food insecurity and low-income in low-input traditional agro-systems. In systems, pesticide-induced adverse impacts on human health and the environment may occur. Setting up an ecologically intensive horticulture by modifying agro-systems to mobilize natural regulation mechanisms taking ecological processes as a source of inspiration, has become a major challenge. This implies a shift from a tactical approach based on preventive and curative chemical treatments (agro-chemistry) to a strategic approach based on preventive and natural methods (agro-ecology) for the regulation of pests/pathogens infestations/infections. Horticultural cropping systems provide ideal frameworks for studying the effects of the planned introduction and management of plant species diversity (PSD), on pest and disease impact. The Cirad Omega3 Project builds on case studies representing a broad range of PSD levels, scales and deployment modalities, according to an a priori typology of pests and diseases based on their life-history traits. Obtained and anticipated outcomes of these studies concern both i) knowledge on ecological pest and disease regulation processes that can be mobilized in horticultural systems, ii) tools and methods for incepting and evaluating innovating pest and disease-resilient cropping systems. We present here the global approach and first results obtained within this framework regarding i) introduction of service plants with sanitizing/ allelopathic effect managed as green manure for reducing tomato bacterial wilt caused by Ralstonia solanacearum, ii) potential of trap crops/barriers for reducing infestation and damage of tomato fruit worms Helicoverpa armigera on okra in Niger and Helicoverpa zea on tomato in Martinique. Results of these case studies on non-specific disease and pests with respectively low and high dispersal ability, provide decision rules which help set up models to predict the impact of PSD deployment modes on the studied bio-aggressors or other pathogens/pests with similar life-history traits. (Resume d'auteur)

Genetic diversity among and within watermelon (Citrullus lanatus) landraces in Southern Africa

SummaryGenetic diversity in watermelon (Citrullus lanatus) was estimated among 213 seedlings from 22 accessions collected in Botswana, Namibia, South Africa, Zambia, and Zimbabwe. The accessions consisted of two types of watermelon landraces: sweet watermelon (C. lanatus var. lanatus) and cow-melon (C. lanatus var. citroides), also known as citron melon. In addition, three commercial varieties of C. lanatus var. lanatus from the USA were included for comparison. Ten simple sequence repeat (SSR; microsatellite) loci detected a total of 153 alleles. The polymorphic information content (PIC) ranged from 0.833 – 0.963, suggesting sufficient discriminatory power. Both a cluster analysis and a principal co-ordinate analysis produced two major clusters, one with the 13 cow-melon accessions and the other with the 12 sweet watermelon accessions. Within the sweet watermelon cluster, the three US cultivars grouped together with the Botswana accessions. Some of the other accessions also grouped according to their country of origin, but others did not. Within-accession diversity parameters showed that those sweet watermelon accessions found in traditional agrosystems were just as genetically variable as the cow-melon accessions.

Agrodiversity in the traditional agrosystems of the Rif mountains (north of Morocco)

The main objective of this study is to evaluate the agrodiversity in the traditional agrosystems of the Rif. The local varieties, marginal crops, neglected and ∖ or underused natural resources and the traditional knowledge were inventoried. This study is based on inquiries to farmers and grains storekeepers. The fruit varieties are remarkable in number so that arboriculture constitutes an essential element of the Rif agrosystems. These various crops are represented by local varieties, which are cultivated in well specified areas with limited exchanges among different regions. Fruit trees are harvested from natural areas. The protection of biodiversity can only be a result of persistence and the maintenance of this agricultural richness. Ecological damage and risks to agriculture such as introduction of selected varieties and the culture of cannabis can be avoided by e valuation and exploitation of this rich genetic heritage.